Ammonium carbonate

Carcinogenicity

Administrative data

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: The test system is unsuitable for assessing the carcinogen potential of NaHCO3, as the rats have been pre-treated with BBN.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1989

Materials and methods

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Sodium hydrogencarbonate

EC Number:

205-633-8

EC Name:

Sodium hydrogencarbonate

Cas Number:

144-55-8

IUPAC Name:

sodium hydrogen carbonate

Details on test material:

- Source: British Drug House, UK.
- Purity: > 99.9%

Test animals

Species:

rat

Strain:

Wistar

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: TNO Voeding AJ Zeist
- Age: 5 weeks.
- Number of animals: 120 in total, 20 in each of 6 groups.

Administration / exposure

Route of administration:

oral: feed

Vehicle:

other: feed

Details on exposure:

VEHICLE
- Concentration in vehicle: Rats were fed with a control diet (group 1) or diet supplemented with equimolar amounts of the following minerals: 2.34% NaCl (group 2), 2.98% KCl (group 3), 3.36% NaHCO3 (group 4), 1.68% NaHCO3 + 2% KHCO3 (group 5), or 4% KHCO3 (group 6).

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

The rats were pre-exposed to 0.05% N-butyl-N- (4-hydroxybutyl)nitrosamine (BBN) in drinking water for four weeks to initiate tumour formation, and then exposed for 32 weeks.

Frequency of treatment:

Continously

Post exposure period:

No.

Doses / concentrations

Remarks:

Doses / Concentrations:
Rats were fed with a control diet (group 1) or diet supplemented with equimolar amounts of the following minerals: 2.34% NaCl (group 2), 2.98% KCl (group 3), 3.36% NaHCO3 (group 4), 1.68% NaHCO3 + 2% KHCO3 (group 5), or 4% KHCO3 (group 6).
Basis:
nominal in diet

Control animals:

yes

Examinations

Observations and examinations performed and frequency:

CLINICAL OBSERVATIONS AND FREQUENCY
- Body weight: It is reported that is was "measured periodically", with no further details.
- Food consumption: It is reported that is was "measured periodically", with no further details.
- Water consumption: It is reported that is was "measured periodically", with no further details.
- Urinalysis: Performed in week 9, 13, 24, 36. Volume, density, Na, K, Cl, Ca, Mg, P and S were measured.

Sacrifice and pathology:

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC):
- Macroscopic: Urinary bladder.
- Microscopic: Urinary bladder

Statistics:

Analysis of variance techniques followed by Dunnett's multiple comparison test (body weight) or by the LSD test (food/water intake, urinalyses). Urinary pH values analysed with the Mann/Whitney U-test. Data on microscopical lesions were analyses with the two-sided Fischer exact probability test (incidences) or Student's t-test.

Results and discussion

Results of examinations

Details on results:

The incidence of papillary or nodular hyperplasia, papillomas and carcinomas increased in rats fed NaHCO3 only if they had been pretreated with BBN. There was no control group with animals fed NaHCO3 that had not been pretreated with BBN.